Mobile data usage has been increasing at an exponential rate in recent year. A Long-Term Evolution (LTE) system offers high peak data rates, low latency, improved system capacity, and low operating cost resulting from simplified network architecture. In LTE systems, an evolved universal terrestrial radio access network (E-UTRAN) includes a plurality of base stations, such as evolved Node-B's (eNBs) communicating with a plurality of mobile stations referred as user equipment (UEs). However, the continuously rising demand for data traffic requires additional solutions. Internetworking between the LTE network and the unlicensed spectrum WLAN provides additional bandwidth to the operators.
However, current approaches suffer from various limitations that hamper the benefits of LTE-WLAN interworking. For example, core network approaches like ANDSF provide rich support for implementing operator policy, providing subscriber specific service, and enabling different kinds of WLAN deployment (e.g., trusted and non-trusted WLANs). However, core network approaches suffer from significant performance shortcomings. These approaches are unable to react to dynamically varying radio conditions and do not permit aggregation of IP flows over LTE and WLAN access. These limitations have been resolved by the Release 12 feature on RAN assisted 3GPP/WLAN interworking. However, R12-IWK only considers UE centric method, which does not have enough network control and access network utilization. For example, the RAN cannot control which UE/UEs to offload traffic to WLAN. The traffic-heavy UE may not be able to move from a heavy-loaded network to a light-loaded network due to the UE-centric instinct, and vice versa. There could still be massive-toggling and ping-pong problems. As a result, Release 13 will standardize the network centric solution (i.e. NCIWK) to let RAN dynamically and efficiently control traffic steering between RAN and WLAN for UEs in both connected mode and idle mode to improve user experience and system efficiency. In addition, due to the contentions on unlicensed spectrum resources, WLAN transmission efficiency was not good and steering UEs to WLAN only based on UE's PHY layer measurements (e.g. beacon RSSU measurement) may fail to get satisfied data rate. In this disclosure, we consider eNB can provide a finer control of WLAN association for the steering UEs in order to improve the transmission efficiency and increase data rate.
Improvements and enhancements are required for finer control of WLAN association for the steering UEs in order to improve the transmission efficiency and increase data.